scholarly journals First detection of stacked X-ray emission from cosmic web filaments

2020 ◽  
Vol 643 ◽  
pp. L2
Author(s):  
H. Tanimura ◽  
N. Aghanim ◽  
A. Kolodzig ◽  
M. Douspis ◽  
N. Malavasi
Keyword(s):  
Point Sources ◽  
Sloan Digital Sky Survey ◽  
Gas Temperature ◽  
Astrophysical Plasma ◽  
X Ray ◽  
Galaxy Groups ◽  
Hot Gas ◽  
Code Model ◽  
Sky Survey ◽  
Statistical Detection

We report the first statistical detection of X-ray emission from cosmic web filaments in ROSAT data. We selected 15 165 filaments at 0.2 <  z <  0.6 ranging from 30 Mpc to 100 Mpc in length, identified in the Sloan Digital Sky Survey survey. We stacked the X-ray count-rate maps from ROSAT around the filaments, excluding resolved galaxy groups and clusters above the mass of ∼3 × 1013 M⊙ as well as the detected X-ray point sources from the ROSAT, Chandra, and XMM-Newton observations. The stacked signal results in the detection of the X-ray emission from the cosmic filaments at a significance of 4.2σ in the energy band of 0.56−1.21 keV. The signal is interpreted, assuming the Astrophysical Plasma Emission Code model, as an emission from the hot gas in the filament-core regions with an average gas temperature of 0.9−0.6+1.0 keV and a gas overdensity of δ ∼ 30 at the center of the filaments. Furthermore, we show that stacking the SRG/eROSITA data for ∼2000 filaments only would lead to a ≳5σ detection of their X-ray signal, even with an average gas temperature as low as ∼0.3 keV.

scholarly journals Detection of intercluster gas in superclusters using the thermal Sunyaev–Zel’dovich effect

2019 ◽  
Vol 625 ◽  
pp. A67 ◽  
Author(s):  
H. Tanimura ◽  
N. Aghanim ◽  
M. Douspis ◽  
A. Beelen ◽  
V. Bonjean
Keyword(s):  
Total Mass ◽  
Baryon Density ◽  
Sloan Digital Sky Survey ◽  
X Ray ◽  
Galaxy Groups ◽  
Hot Gas ◽  
Sky Survey ◽  
Sunyaev Zel'dovich Effect ◽  
Optical Surveys ◽  
Intracluster Gas

Using a thermal Sunyaev–Zel’dovich (tSZ) signal, we search for hot gas in superclusters identified using the Sloan Digital Sky Survey Data Release 7 (SDSS/DR7) galaxies. We stack a Comptonization y map produced by the Planck Collaboration around the superclusters and detect the tSZ signal at a significance of 6.4σ. We further search for an intercluster component of gas in the superclusters. For this, we remove the intracluster gas in the superclusters by masking all galaxy groups/clusters detected by the Planck tSZ, ROSAT X-ray, and SDSS optical surveys down to a total mass of 1013 M⊙. We report the first detection of intercluster gas in superclusters with y = (3.5 ± 1.4) × 10−8 at a significance of 2.5σ. Assuming a simple isothermal and flat density distribution of intercluster gas over superclusters, the estimated baryon density is (Ωgas/Ωb)×(Te/8 × 106 K) = 0.067 ± 0.006 ± 0.025. This quantity is inversely proportional to the temperature, therefore taking values from simulations and observations, we find that the gas density in superclusters may account for 17–52% of missing baryons at low redshifts. A better understanding of the physical state of gas in the superclusters is required to accurately estimate the contribution of our measurements to missing baryons.

scholarly journals The XXL Survey

2018 ◽  
Vol 620 ◽  
pp. A8 ◽  
Author(s):  
Arya Farahi ◽  
Valentina Guglielmo ◽  
August E. Evrard ◽  
Bianca M. Poggianti ◽  
Christophe Adami ◽  
...  
Keyword(s):  
Dark Matter ◽  
Velocity Dispersion ◽  
Gas Temperature ◽  
X Ray ◽  
Galaxy Groups ◽  
Hot Gas ◽  
Low Mass ◽  
Massive Halos ◽  
Weak Constraints ◽  
Velocity Bias

Context. An X-ray survey with the XMM-Newton telescope, XMM-XXL, has identified hundreds of galaxy groups and clusters in two 25 deg2 fields. Combining spectroscopic and X-ray observations in one field, we determine how the kinetic energy of galaxies scales with hot gas temperature and also, by imposing prior constraints on the relative energies of galaxies and dark matter, infer a power-law scaling of total mass with temperature. Aims. Our goals are: i) to determine parameters of the scaling between galaxy velocity dispersion and X-ray temperature, T300 kpc, for the halos hosting XXL-selected clusters, and; ii) to infer the log-mean scaling of total halo mass with temperature, ⟨lnM200 | T300 kpc, z⟩. Methods. We applied an ensemble velocity likelihood to a sample of >1500 spectroscopic redshifts within 132 spectroscopically confirmed clusters with redshifts z < 0.6 to model, ⟨lnσgal | T300 kpc, z⟩, where σgal is the velocity dispersion of XXL cluster member galaxies and T300 kpc is a 300 kpc aperture temperature. To infer total halo mass we used a precise virial relation for massive halos calibrated by N-body simulations along with a single degree of freedom summarising galaxy velocity bias with respect to dark matter. Results. For the XXL-N cluster sample, we find σgal ∝ T300 kpc0.63±0.05, a slope significantly steeper than the self-similar expectation of 0.5. Assuming scale-independent galaxy velocity bias, we infer a mean logarithmic mass at a given X-ray temperature and redshift, 〈ln(E(z)M200/1014 M⊙)|T300 kpc, z〉 = πT + αT ln (T300 kpc/Tp) + βT ln (E(z)/E(zp)) using pivot values kTp = 2.2 keV and zp = 0.25, with normalization πT = 0.45 ± 0.24 and slope αT = 1.89 ± 0.15. We obtain only weak constraints on redshift evolution, βT = −1.29 ± 1.14. Conclusions. The ratio of specific energies in hot gas and galaxies is scale dependent. Ensemble spectroscopic analysis is a viable method to infer mean scaling relations, particularly for the numerous low mass systems with small numbers of spectroscopic members per system. Galaxy velocity bias is the dominant systematic uncertainty in dynamical mass estimates.

scholarly journals High-redshift galaxy groups as seen by ATHENA/WFI

2020 ◽  
Vol 642 ◽  
pp. A17
Author(s):  
Chaoli Zhang ◽  
Miriam E. Ramos-Ceja ◽  
Florian Pacaud ◽  
Thomas H. Reiprich
Keyword(s):  
High Redshift ◽  
High Energy ◽  
Wide Field ◽  
Gas Temperature ◽  
X Ray ◽  
Galaxy Groups ◽  
Hot Gas ◽  
Redshift Galaxy ◽  
Custom Made ◽  
Early Galaxy

Context. The first massive galaxy groups in the Universe are predicted to have formed at redshifts well beyond two. Baryonic physics, like stellar and active galactic nuclei (AGN) feedback in this very active epoch, are expected to have left a strong imprint on the thermo-dynamic properties of these early galaxy groups. Therefore, observations of these groups are key to constrain the relative importance of these physical processes. However, current instruments are not sensitive enough to detect them easily and characterize their hot gas content. Aims. In this work, we quantify the observing power of the Advanced Telescope for High ENergy Astrophysics (ATHENA), the future large X-ray observatory of the European Space Agency, for discovering and characterizing early galaxy groups at high redshifts. We also investigate how well ATHENA will constrain different feedback mechanisms. Methods. We used the SImulation of X-ray TElescopes simulator to mimic ATHENA observations, and a custom-made wavelet-based algorithm to detect galaxy groups and clusters in the redshift range 0.5 ≤ z ≤ 4. We performed extensive X-ray spectral fitting in order to characterize their gas temperature and X-ray luminosity. In the simulations and their analysis, we took into account the main ATHENA instrumental features: background, vignetting, and point spread function degradation with off-axis angle, as well as all X-ray foreground and background components including a realistic AGN flux distribution. Different physically motivated thermo-dynamical states of galaxy groups were simulated and tested, including central AGN contamination, different scaling relation models (luminosity evolution), and distinct surface brightness profiles. Also, different ATHENA instrumental setups were tested, including both 15 and 19 mirror rows and the applied optical blocking filter. Results. In the deep Wide Field Imager survey expected to be carried out during part of ATHENA’s first four years (the nominal mission lifetime) more than 10 000 galaxy groups and clusters at z ≥ 0.5 will be discovered. We find that ATHENA can detect ∼20 high-redshift galaxy groups with masses of M500 ≥ 5 × 1013 M⊙ and z ≥ 2, and almost half of them will have a gas temperature determined to a precision of ΔT/T ≤ 25%. Conclusions. We demonstrate that high-redshift galaxy groups can be detected very efficiently as extended sources by ATHENA and that a key parameter determining the total number of such newly discovered sources is the area on the sky surveyed by ATHENA. We show that these observations have a very good potential to constrain the importance of different feedback processes in the early universe because of ATHENA’s ability not only to find the early groups but also to characterize their hot gas properties at the same time.

scholarly journals Hoinga: a supernova remnant discovered in the SRG/eROSITA All-Sky Survey eRASS1

2021 ◽  
Vol 648 ◽  
pp. A30
Author(s):  
W. Becker ◽  
N. Hurley-Walker ◽  
Ch. Weinberger ◽  
L. Nicastro ◽  
M. G. F. Mayer ◽  
...  
Keyword(s):  
Supernova Remnants ◽  
Galactic Plane ◽  
Point Sources ◽  
Galactic Latitude ◽  
Gas Temperature ◽  
High Galactic Latitude ◽  
X Ray ◽  
Flux Limit ◽  
Sky Survey ◽  
The Universe

Supernova remnants (SNRs) are observable for about (6−15) × 104 yr before they fade into the Galactic interstellar medium. With a Galactic supernova rate of approximately two per century, we can expect to have of the order of 1200 SNRs in our Galaxy. However, only about 300 of them are known to date, with the majority having been discovered in Galactic plane radio surveys. Given that these SNRs represent the brightest tail of the distribution and are mostly located close to the plane, they are not representative of the complete sample. The launch of the Russian-German observatory SRG/eROSITA in July 2019 brought a promising new opportunity to explore the Universe. Here we report findings from the search for new SNRs in the eROSITA all-sky survey data which led to the detection of one of the largest SNRs discovered at wavelengths other than the radio: G249.5+24.5. This source is located at a relatively high Galactic latitude, where SNRs are not usually expected to be found. The remnant, ‘Hoinga’, has a diameter of about 4. °4 and shows a circular shaped morphology with diffuse X-ray emission filling almost the entire remnant. Spectral analysis of the remnant emission reveals that an APEC spectrum from collisionally ionised diffuse gas and a plane-parallel shock plasma model with non-equilibrium ionisation are both able to provide an adequate description of the data, suggesting a gas temperature of the order of kT = 0.1−0.02+0.02 keV and an absorbing column density of NH = 3.6−0.6+0.7 × 1020 cm−2. Various X-ray point sources are found to be located within the remnant boundary but none seem to be associated with the remnant itself. Subsequent searches for a radio counterpart of the Hoinga remnant identified its radio emission in archival data from the Continuum HI Parkes All-Sky Survey and the 408-MHz ‘Haslam’ all-sky survey. The radio spectral index α = −0.69 ± 0.08 obtained from these data definitely confirms the SNR nature of Hoinga. We also analysed INTEGRAL SPI data for fingerprints of 44Ti emission, which is an ideal candidate with which to study nucleosynthesis imprinting in young SNRs. Although no 44Ti emission from Hoinga was detected, we were able to set a 3σ upper flux limit of 9.2 × 10−5 ph cm−2 s−1. From its size and X-ray and radio spectral properties we conclude that Hoinga is a middle-aged Vela-like SNR located at a distance of about twice that of the Vela SNR, i.e. at ~500 pc.

scholarly journals Density and temperature of cosmic-web filaments on scales of tens of megaparsecs

2020 ◽  
Vol 637 ◽  
pp. A41 ◽  
Author(s):  
H. Tanimura ◽  
N. Aghanim ◽  
V. Bonjean ◽  
N. Malavasi ◽  
M. Douspis
Keyword(s):  
Physical Properties ◽  
Large Scale ◽  
Sloan Digital Sky Survey ◽  
Gas Temperature ◽  
Matter Distribution ◽  
Microwave Background ◽  
Galaxy Groups ◽  
Sky Survey ◽  
Dark Matter Distribution ◽  
First Time

We studied physical properties of matter in 24 544 filaments ranging from 30 to 100 Mpc in length, identified in the Sloan Digital Sky Survey. We stacked the Comptonization y map produced by the Planck Collaboration around the filaments, excluding the resolved galaxy groups and clusters above a mass of ∼3 × 1013 M⊙. We detected the thermal Sunyaev-Zel’dovich signal for the first time at a significance of 4.4σ in filamentary structures on such a large scale. We also stacked the Planck cosmic microwave background lensing convergence map in the same manner and detected the lensing signal at a significance of 8.1σ. To estimate physical properties of the matter, we considered an isothermal cylindrical filament model with a density distribution following a β-model (β = 2/3). Assuming that the gas distribution follows the dark matter distribution, we estimate that the central gas and matter overdensity δ and gas temperature Te are δ = 19.0−12.1+27.3 and Te = 1.4−0.4+0.4 × 106 K, which results in a measured baryon fraction of 0.080−0.051+0.116 × Ωb.

scholarly journals CODEX clusters

2020 ◽  
Vol 638 ◽  
pp. A114 ◽  
Author(s):  
A. Finoguenov ◽  
E. Rykoff ◽  
N. Clerc ◽  
M. Costanzi ◽  
S. Hagstotz ◽  
...  
Keyword(s):  
Galaxy Clusters ◽  
Sample Selection ◽  
Sloan Digital Sky Survey ◽  
Selection Function ◽  
Large Area ◽  
X Ray ◽  
Galaxy Groups ◽  
Sky Survey ◽  
Area X

Context. Large area catalogs of galaxy clusters constructed from ROSAT All-Sky Survey provide the basis for our knowledge of the population of clusters thanks to long-term multiwavelength efforts to follow up observations of these clusters. Aims. The advent of large area photometric surveys superseding previous, in-depth all-sky data allows us to revisit the construction of X-ray cluster catalogs, extending the study to lower cluster masses and higher redshifts and providing modeling of the selection function. Methods. We performed a wavelet detection of X-ray sources and made extensive simulations of the detection of clusters in the RASS data. We assigned an optical richness to each of the 24 788 detected X-ray sources in the 10 382 square degrees of the Baryon Oscillation Spectroscopic Survey area using red sequence cluster finder redMaPPer version 5.2 run on Sloan Digital Sky Survey photometry. We named this survey COnstrain Dark Energy with X-ray (CODEX) clusters. Results. We show that there is no obvious separation of sources on galaxy clusters and active galactic nuclei (AGN) based on the distribution of systems on their richness. This is a combination of an increasing number of galaxy groups and their selection via the identification of X-ray sources either by chance or by groups hosting an AGN. To clean the sample, we use a cut on the optical richness at the level corresponding to the 10% completeness of the survey and include it in the modeling of the cluster selection function. We present the X-ray catalog extending to a redshift of 0.6. Conclusions. The CODEX suvey is the first large area X-ray selected catalog of northern clusters reaching fluxes of 10−13 ergs s−1 cm−2. We provide modeling of the sample selection and discuss the redshift evolution of the high end of the X-ray luminosity function (XLF). Our results on z <  0.3 XLF agree with previous studies, while we provide new constraints on the 0.3 <  z <  0.6 XLF. We find a lack of strong redshift evolution of the XLF, provide exact modeling of the effect of low number statistics and AGN contamination, and present the resulting constraints on the flat ΛCDM.

scholarly journals Survey of Gravitationally Lensed Objects in HSC Imaging (SuGOHI) – VII. Discovery and confirmation of three strongly lensed quasars†

2021 ◽  
Vol 502 (1) ◽  
pp. 1487-1493
Author(s):  
Anton T Jaelani ◽  
Cristian E Rusu ◽  
Issha Kayo ◽  
Anupreeta More ◽  
Alessandro Sonnenfeld ◽  
...  
Keyword(s):  
Spectroscopic Data ◽  
Point Sources ◽  
Sloan Digital Sky Survey ◽  
Early Type ◽  
Blue Point ◽  
X Ray ◽  
Quasar Spectra ◽  
Strategic Program ◽  
Early Type Galaxy

ABSTRACT We present spectroscopic confirmation of three new two-image gravitationally lensed quasars, compiled from existing strong lens and X-ray catalogues. Images of HSC J091843.27–022007.5 show a red galaxy with two blue point sources at either side, separated by 2.26 arcsec. This system has a source and a lens redshifts zs = 0.804 and zℓ = 0.459, respectively, as obtained by our follow-up spectroscopic data. CXCO J100201.50+020330.0 shows two point sources separated by 0.85 arcsec on either side of an early-type galaxy. The follow-up spectroscopic data confirm the fainter quasar has the same redshift with the brighter quasar from the Sloan Digital Sky Survey (SDSS) fiber spectrum at zs = 2.016. The deflecting foreground galaxy is a typical early-type galaxy at a redshift of zℓ = 0.439. SDSS J135944.21+012809.8 has two point sources with quasar spectra at the same redshift zs = 1.096, separated by 1.05 arcsec, and fits to the HSC images confirm the presence of a galaxy between these. These discoveries demonstrate the power of the Hyper Suprime-Cam Subaru Strategic Program (HSC-SSP)’s deep imaging and wide sky coverage. Combined with existing X-ray source catalogues and follow-up spectroscopy, the HSC-SSP provides us unique opportunities to find multiple-image quasars lensed by a foreground galaxy.

scholarly journals Clustering and Halo Occupation Distribution of Active Galactic Nuclei

2013 ◽  
Vol 9 (S304) ◽  
pp. 243-243
Author(s):  
Takamitsu Miyaji ◽  
M. Krumpe ◽  
A. Coil ◽  
H. Aceves ◽  
B. Husemann
Keyword(s):  
Cross Correlation ◽  
Dynamic Range ◽  
Signal To Noise Ratio ◽  
Sloan Digital Sky Survey ◽  
Dark Matter Halo ◽  
Bias Parameter ◽  
X Ray ◽  
Sky Survey ◽  
Galaxy Population ◽  
Halo Occupation Distribution

AbstractWe present the results of our series of studies on correlation function and halo occupation distribution of AGNs utilizing data the ROSAT All-Sky Survey (RASS) and the Sloan Digital Sky Survey (SDSS) in the redshift range of 0.07<z<0.36. In order to improve the signal-to-noise ratio, we take cross-correlation approach, where cross-correlation functions (CCF) between AGNs and much more numerous AGNs are analyzed. The calculated CCFs are analyzed using the Halo Occupation Distribution (HOD) model, where the CCFs are divided into the term contributed by the AGN-galaxy pairs that reside in one dark matter halo (DMH), (the 1-halo term) and those from two different DMHs (the 2-halo term). The 2-halo term is the indicator of the bias parameter, which is a function of the typical mass of the DMHs in which AGNs reside. The combination of the 1-halo and 2-halo terms gives, not only the typical DMH mass, but also how the AGNs are distributed among the DMHs as a function of mass separately for those at the center of the DMHs and satellites. The main results are as follows: (1) the range of typical mass of the DMHs in various sub-samples of AGNs log (MDMH/h−1MΘ) ~ 12.4–13.4, (2) we found a dependence of the AGN bias parameter on the X-ray luminosity of AGNs, while the optical luminosity dependence is not significant probably due to smaller dynamic range in luminosity for the optically-selected sample, and (3) the growth of the number of AGNs per DMH (N (MDMH)) with MDMH is shallow, or even may be flat, contrary to that of the galaxy population in general, which grows with MDMH proportionally, suggesting a suppression of AGN triggering in denser environment. In order to investigate the origin of the X-ray luminosity dependence, we are also investigating the dependence of clustering on the black hole mass and the Eddington ratio, we also present the results of this investigation.

scholarly journals X-Ray Emission from Expanding Shells in NGC 3077

2004 ◽  
Vol 217 ◽  
pp. 310-311
Author(s):  
Jürgen Ott ◽  
Crystal L. Martin ◽  
Fabian Walter
Keyword(s):  
Thermal Emission ◽  
Dwarf Galaxy ◽  
Point Sources ◽  
Starburst Galaxy ◽  
Interstellar Gas ◽  
X Ray ◽  
Hot Gas ◽  
Hα Emission ◽  
Emission Models ◽  
Expanding Shells

Deep Chandra observations of NGC 3077, a starburst dwarf galaxy in the M81 triplet, resolve the X-ray emission from several supershells. The emission is brightest in the cavities defined by expanding shells detected previously in Hα emission. Thermal emission models fitted to the data imply temperatures ranging from 1.3 to 4.9 × 106 K. The total 0.3–6.0 keV X-ray luminosity is 2 − 5 × 1039ergs−1 (depending on the selected thermal plasma model). Most (85%) of the X-ray luminosity in NGC 3077 comes from the hot interstellar gas; the remainder comes from six X-ray point sources. The radial density profile of the hot gas is not as steep as that expected in a freely expanding wind (e.g., as seen in the neighboring starburst galaxy M 82) implying that the hot gas is still confined by the Hα shells.

scholarly journals Redshift measurement through star formation

2019 ◽  
Vol 629 ◽  
pp. A7
Author(s):  
Mikkel O. Lindholmer ◽  
Kevin A. Pimbblet
Keyword(s):  
Star Formation ◽  
Galaxy Clusters ◽  
Main Sequence ◽  
Formation Rate ◽  
Sloan Digital Sky Survey ◽  
X Ray ◽  
Star Forming ◽  
Sky Survey ◽  
The Galaxy ◽  
Galaxy Population

In this work we use the property that, on average, star formation rate increases with redshift for objects with the same mass – the so called galaxy main sequence – to measure the redshift of galaxy clusters. We use the fact that the general galaxy population forms both a quenched and a star-forming sequence, and we locate these ridges in the SFR–M⋆ plane with galaxies taken from the Sloan Digital Sky Survey in discrete redshift bins. We fitted the evolution of the galaxy main sequence with redshift using a new method and then subsequently apply our method to a suite of X-ray selected galaxy clusters in an attempt to create a new distance measurement to clusters based on their galaxy main sequence. We demonstrate that although it is possible in several galaxy clusters to measure the main sequences, the derived distance and redshift from our galaxy main sequence fitting technique has an accuracy of σz = ±0.017 ⋅ (z + 1) and is only accurate up to z ≈ 0.2.

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